This invention relates to a liquid jet recording head, and more particularly to a liquid jet recording head used in an on-demand type liquid jet recording apparatus to discharge recording liquid and form flying liquid droplets.
2. Related Background Art
As an on-demand type liquid jet recording head, there is typically known one of the type in which a piezo-electric element, which is an electromechanical converting element or a magneto-strictive element is utilized to impart a sudden pressure force to the liquid in a discharge generating portion, thereby accomplishing discharge of liquid droplets. In a recording head of this type ink droplets can be discharged from orifices only when required for printing, and has the great merit that means for collecting unnecessary ink and a high voltage source for deflection are not required. On the other hand, a liquid jet recording head of this type has the disadvantage that the discharge repetition frequency is relatively low and therefore the printing speed is low, and also involves the problem that if the repetition frequency is increased, it becomes difficult for uniform droplets to be formed in a stable condition and this gives rise to an irregularity in the liquid droplet discharge speed which also makes stable recording difficult to obtain.
A method in which liquid acted by the heat energy creates a change of phase which results in a rapid increase in volume and in which liquid is jetted from an orifice is known as on-demand type liquid jet recording method (See DOLS-2843064).
A liquid jet recording head employing the above method enables implementation of a recording head of a full line type having a high density multiorifice head and can provide high quality image at a high speed.
However, further high speed printing and the further stability of the ink jet recording head have been recently required.
To solve such a problem, a liquid jet recording head has been proposed which, as disclosed, for example, in Japanese Laid-Open Patent Application Nos. 1569/1983 and 1570/1983, has orifices for discharging liquid and forming flying droplets and in which energy generating members generating energy for forming liquid droplets are provided in liquid paths for directing the liquid from a liquid chamber to the orifices and wherein the flow paths are formed so that the cross-sectional are thereof is gradually decreased from the liquid chamber toward the orifices.
However, the realization of the higher speed recording and the more stable recording in the ink jet recording head results in dense recording and the high grade recording and therefore the above requirements are always required.
In recent years, the requirements for higher performance of the ink jet recording apparatus, for example, higher printing speed and stable recording quality, have been increasing and recording heads of higher quality have been desired.